Variation in the time between fires, their severity, size and patchiness, and the season in which they occur is called ‘pyrodiversity’. Because plants and animals often depend on resources that vary as a result of fire, it is argued that pyrodiversity will produce a diversity of habitats that can support more species. Some studies demonstrate that more plants and animals live in areas with a high diversity of fire histories, while others show no such relationship, challenging the generality of the hypothesis that ‘pyrodiversity promotes biodiversity’.
Relationships between fire and biodiversity are context-specific, and vary between species, ecosystems and across spatial scales. For example, pyrodiversity increases bird diversity in eucalypt forests and plant-pollinator diversity in mixed-conifer forests. By contrast, unqualified application of pyrodiversity could reduce diversity of vertebrates in mallee vegetation, and ants and termites in savannas are relatively resilient to variation in fire regimes.
Ecological heterogeneity is important for biodiversity conservation, but not all forms of fire-driven variation are desirable. The ability to identify consistent relationships between pyrodiversity and biodiversity is complicated by feedbacks with other ecological processes. For example, climate, grazing and predation strongly affect fire and biodiversity, as well as relationships between them.
How can scientists and decision makers use the pyrodiversity concept for biodiversity conservation? Foremost, it is essential to recognise that there is no ‘one-size-fits-all’ approach. Natural ecosystems contain different species, have different fire regimes and present different fire risks to biodiversity and people. Fire management will be more effective when guided by local knowledge and based on the demonstrated requirements of plants and animals, as well as the habitats they depend on.